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Code Issues Releases Wiki Activity

net/packet: remove po->xmit

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Use PACKET_SOCK_QDISC_BYPASS atomic bit instead of a pointer.

This removes one indirect call in fast path,
and READ_ONCE()/WRITE_ONCE() annotations as well.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Willem de Bruijn <willemb@google.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2023-03-17 16:20:02 +00:00 committed by David S. Miller
parent 72abf21799
commit 105a201ebf
2 changed files with 10 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

24
net/packet/af_packet.c
View file

@ -270,8 +270,11 @@ static noinline struct sk_buff *nf_hook_direct_egress(struct sk_buff *skb)
}
#endif
static int packet_direct_xmit(struct sk_buff *skb)
static int packet_xmit(const struct packet_sock *po, struct sk_buff *skb)
{
if (!packet_sock_flag(po, PACKET_SOCK_QDISC_BYPASS))
return dev_queue_xmit(skb);
#ifdef CONFIG_NETFILTER_EGRESS
if (nf_hook_egress_active()) {
skb = nf_hook_direct_egress(skb);
@ -305,12 +308,6 @@ static void packet_cached_dev_reset(struct packet_sock *po)
RCU_INIT_POINTER(po->cached_dev, NULL);
}
static bool packet_use_direct_xmit(const struct packet_sock *po)
{
/* Paired with WRITE_ONCE() in packet_setsockopt() */
return READ_ONCE(po->xmit) == packet_direct_xmit;
}
static u16 packet_pick_tx_queue(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
@ -2872,8 +2869,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
packet_inc_pending(&po->tx_ring);
status = TP_STATUS_SEND_REQUEST;
/* Paired with WRITE_ONCE() in packet_setsockopt() */
err = READ_ONCE(po->xmit)(skb);
err = packet_xmit(po, skb);
if (unlikely(err != 0)) {
if (err > 0)
err = net_xmit_errno(err);
@ -3076,8 +3072,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
virtio_net_hdr_set_proto(skb, &vnet_hdr);
}
/* Paired with WRITE_ONCE() in packet_setsockopt() */
err = READ_ONCE(po->xmit)(skb);
err = packet_xmit(po, skb);
if (unlikely(err != 0)) {
if (err > 0)
err = net_xmit_errno(err);
@ -3359,7 +3355,6 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
init_completion(&po->skb_completion);
sk->sk_family = PF_PACKET;
po->num = proto;
po->xmit = dev_queue_xmit;
err = packet_alloc_pending(po);
if (err)
@ -4010,8 +4005,7 @@ packet_setsockopt(struct socket *sock, int level, int optname, sockptr_t optval,
if (copy_from_sockptr(&val, optval, sizeof(val)))
return -EFAULT;
/* Paired with all lockless reads of po->xmit */
WRITE_ONCE(po->xmit, val ? packet_direct_xmit : dev_queue_xmit);
packet_sock_flag_set(po, PACKET_SOCK_QDISC_BYPASS, val);
return 0;
}
default:
@ -4126,7 +4120,7 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
val = packet_sock_flag(po, PACKET_SOCK_TX_HAS_OFF);
break;
case PACKET_QDISC_BYPASS:
val = packet_use_direct_xmit(po);
val = packet_sock_flag(po, PACKET_SOCK_QDISC_BYPASS);
break;
default:
return -ENOPROTOOPT;

2
net/packet/internal.h
View file

@ -128,7 +128,6 @@ struct packet_sock {
unsigned int tp_tstamp;
struct completion skb_completion;
struct net_device __rcu *cached_dev;
int (*xmit)(struct sk_buff *skb);
struct packet_type prot_hook ____cacheline_aligned_in_smp;
atomic_t tp_drops ____cacheline_aligned_in_smp;
};
@ -143,6 +142,7 @@ enum packet_sock_flags {
PACKET_SOCK_HAS_VNET_HDR,
PACKET_SOCK_RUNNING,
PACKET_SOCK_PRESSURE,
PACKET_SOCK_QDISC_BYPASS,
};
static inline void packet_sock_flag_set(struct packet_sock *po,